jetting

[jsl1213]

does anybody know if you have to rejet if you go from a fmf megamax to a Q4 or a powercore 4 ?

[Ian400ex]

First sign is irregular sounds (popping/cracking, etc).

Only way to be precise, though, is by plug chops. I can't explain this however.

Search or wait for another person to explain it.

[honda400ex2003]

if it is jetted already most likely not. should be around a 150-152 on the main already so that will be fine with either one of those. btw, i like my q4 great quiet exhaust :D. steve